Newborn left to die in 1981 identified by DNA; mother charged in South Dakota

Theresa Bentaas, 57, is suspected to be the baby's biological mother. She was arrested for allegedly leaving him to die on the side of a South Dakota road in 1981. (Source: KSFY)

March 13, 2019 at 6:43 AM EDT - Updated March 14 at 12:10 PM

SIOUX FALLS, SD (KSFY/Gray News) - Police say a 38-year-old cold case in which an unknown newborn died on the side of the road has been solved, thanks to DNA tests and genealogy that helped find the baby’s suspected mother, KSFY reports.

Theresa Bentaas, 57, was arrested Friday for allegedly leaving her son, dubbed by media as baby Andrew, to die in 1981. She is charged with three alternative counts of first degree murder, second degree murder and first degree manslaughter.

If convicted, she could be sentenced to death or life in prison.

Theresa Bentaas, 57, is suspected to be the baby's biological mother. She was arrested for allegedly leaving him to die on the side of a South Dakota road in 1981. (Source: KSFY) (Source: KSFY)

Detective Mike Webb with the Sioux Falls Police Department has not stopped trying to solve the case, ever since he was first assigned to it in 2009. He says he worked hard, knowing a child was involved.

“You go through a lot of frustrations. You get knocked down a lot. But you keep getting back up, and you don’t quit,” he said.

The department recently teamed up with a company called Parabon Labs, which had some success with cold cases in the past. Last year, it used genetics in the “Golden State Killer” case to help arrest a California man in connection to 13 murders and dozens of rapes from the 70s and 80s.

"Over the last few months, we worked with Parabon Labs with the baby’s DNA. Their genealogist became involved, and a few weeks ago ... they were able to determine some family trees for us,” Webb said.

From there, Webb identified Bentaas as baby Andrew’s mother through DNA information and genealogy websites. Swab samples later confirmed she and her husband were the boy’s biological parents, according to the detective.

Webb says he’s glad the technology helped make an arrest and provide closure, as he heads into retirement.

“It’s amazing to have, finally, some closure on this case,” he said. “I think his voice is heard.”

Because the baby, dubbed Andrew by the media, was left to die in 1981, the laws will be applied in the case as they were written at the time. (Source: Sioux Falls Police Department/KSFY/CNN) (Source: Sioux Falls Police Department/KSFY/CNN)

Attorney Scott Swier, who is not involved in the case, says the DNA evidence appears to be very strong and will play a vital role if it goes to trial.

"It’s shown how far technology has evolved since the 1980s, to the point where that technology wasn’t available then. And to now have the technology get better to the point that we’re talking odds of 1 to 1 trillion is pretty incredible,” he said.

Bentaas is being held on a $250,000 bond. Up until she was arrested, she lived with her husband in Sioux Falls, SD, and has two kids.

The suspect allegedly admitted to the crime in interviews with investigators, telling them she had been “young and stupid” at the time.

Webb says Bentaas’ husband did not know about the baby and is not facing any charges.

The man who found baby Andrew in 1981, Lee Litz, attended Bentaas’ Monday court hearing. His daughter says he came to show support for the newborn because he never really had a family.

“I think about what he’d be doing today if he was around and would have had a chance,” Litz said. “I just wish I could have found him a little sooner. But it wasn’t to be.”

The man who found baby Andrew in 1981, Lee Litz, attended the suspect's first court hearing. His daughter says he came to show support for the newborn because he never really had a family. (Source: KSFY/Sioux Falls Police Department/CNN) (Source: KSFY/Sioux Falls Police Department/CNN)

Because the crime happened in 1981, the laws will be applied in the case as they were written at the time.

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